1. Field of the Invention
Embodiments of the present invention relate to a display device, and more particularly to a display device and a driving method thereof. Embodiments of the present invention are suitable for a wide scope of applications. In particular, embodiments of the present invention are suitable for compensating a lens distortion in a multi-touch recognition for a display device.
2. Description of the Related Art
Generally, a touch panel is a type of user interface that is attached to a display device with the property that an electrical characteristic thereof is changed at a contact point where a hand or a pen touches the panel. Touch panels have been used in various applications, such as in small portable terminals, office equipment and the like. However, if a multi-touch is generated by two or more substantially simultaneous contact points, the touch panel might malfunction or any one of the touches can be selected by a pre-set program.
In order to overcome the limit of multi-touch recognition in the touch panel of the related art, there has recently been developed a multi-touch recognition device which simultaneously recognizes a plurality of touches.
The multi-touch recognition device might wrongly recognize a touch location due to the aberration of lens and the like in case of using a camera having lens. Further, the multi-touch recognition device might have the location of the camera optically misaligned against the touch surface. And, because of this, an offset value exists in the angle of the touch point measured by the camera and there might be induced a difference of as much as the offset from the actual touch point. Recently, there has been an attempt of pre-calculating the offset value generated in accordance with the camera location for the touch surface in the multi-touch recognition device, storing the offset value at the memory, and reflecting the offset value to the touch point. However, the related art has no way of compensating the distortion generated in the lens itself in the multi-touch recognition device.
Further, the multi-touch recognition device has a problem in that a touch recognition circuit is separated from a drive circuit of the display device such that the display action and the touch recognition action are not synchronized, thereby realizing the circuit inefficiently.
Although there is a method of embedding an optical sensor of the multi-touch recognition device in each pixel of the display device, but this method has another problem in that the aperture ratio of the display device is decreased to lower the brightness thereof due to the optical sensor.